量热法依据的原理是（）
A.化学特性
B.生物效应特性
C.热作用
D.荧光作用
E.电离作用
参考答案：C
用所给词的正确形式填空。
1．There are many ________(sheep) on the hill. Some ________(child) are looking after them.
2．Whose is that bike, David? Is it ________(you)? No, It's ________(Jim).
3．We have many ________(friend), they are very ________(friend).
4．Jim can ________(swim) in the river. He often ________(swim). He likes ________(swim) a lot.
5．The twins are ________(America). They are from ________(America).
关中城市群的副中心是（）
A.咸阳
B.宝鸡
C.渭南
D.铜川
